Interactive multi-media centers are characterized by an increasing number of channels of programming available and an increasing amount of functionality offered. The increased number of available channels results from increased program availability from such services as cable and satellites. New types of functionality include recording, time-shifting, and convergence with the Internet. These increases in available programming and functionality result in a dense and complex user interface in an environment that typically does not have a desktop for a mouse or keyboard, the standard input devices for the complex user interfaces typical of personal computers. Rather, the typical user input devices of choice for televisions and multi-media centers is one or more infra-red (IR) remote controls laden with pushbuttons, including arrow, keypad and dedicated function buttons. These button-laden remote controls are utilized for the selection of channels and functions and for onscreen navigation. However, current interactive televisions and multi-media centers now have too many channels and functions for this type of interface to be effective and a more efficient interface is desired.
Preferably, such an interface and controller for the above-mentioned systems would allow efficient navigation, selection and activation in a dense interface that requires fewer individual buttons on the remote control and allows the user to view the screen rather than the remote control while making selections.
To overcome the drawbacks of the conventional remote control device, devices have been developed that replace inputs to the device via buttons and the like with inputs generated by movements or gestures of a user holding the device. These devices track movement by sensing acceleration in the x, y or z dimension via a motion-based sensor disposed in the device. These sensed movements are translated into inputs to navigate an interface, operate an external device, simulate user activity in a gaming system, etc. In fact, motion-based sensors are becoming the man-machine interface of choice for a variety of devices including game controllers, mobile hard drives, consumer remote controls, mobile phones, portable media players, personal digital assistants, among others.
However, in order to detect motion, a device including a motion-based sensor has to continually sample acceleration values to detect changes in the device's position. For example, in a microprocessor based device, the microprocessor has to be running and continuously sampling acceleration measurements. This operation expends a large amount of power, e.g., battery power in a portable device, even when the device is at rest. Therefore, a need exists for techniques for conserving power on devices having such motion-based sensors.